Conversion RPKM in counts using R

Question

[Eisuan]

Hello everyone! Is there any R function able to convert RPKM in counts?

I would like to follow the workflow analysis of a DESeq2 tutorial. Unfortunately, I have two xlsx files of this RNA-seq analysis: one containing avg counts and the other one containing RPKM for each replicate.

What I would like to perform is count quality assessment through hierarchical heatmap by condition and PCA.

[ATpoint]

You would need to exactly know how the RPKM table was made in order to reverse the action. For this you also need the exact gene length that was used for correction. Are these information available?

[Eisuan]

Thank you for your reply. Yes, I could ask directly for the counts matrix. However, I was wondering if it could possible to retrieve the information in another way.

[ATpoint]

I would always start from raw counts if possible.